Working fluid for refrigeration



Patented a. 11, 1927.

UNITED STATES P NT OFFICE.

ANDREW A. xuonnn, or onns'rnn, mam-mum WORKING- IFLUID FOR REFRIGERATION.

-No Drawing. Original application filed April 7, 1922, Serial No. 550,445- Divided and this application filed February 8, I923, Serial No.

This invention relates to the art of 'refrig eration, particularly as practiced by the socalled compression process, and has for an object to provide an improved working fluid 6 for use in rocesses of the, character designated whic ,shall have as constituents a refrigerant and a lubricant admixing therewith to form a homogeneous fluid of such character that the lubricant is not mechan- 10 ically segregated from the refrigerant 1n paslslng through a compression refrigeratlon c c e.

Compression refrigerators nominally comprise a chamber in which a working fluid 1s evaporated at a relatively low pressure and temperature, a chamber in whichthe vapors are condensed at ahigher pressure and temperature, a compression mechanism for translating the vapors from the low-pres.

0 sure evaporation chamber to the high-pres: sure condensing chamber, and a 'valYe con-' duit for returning the condensed flllld' at a reduced pressure into the evaporation chamber. The refrigerant fluid t us flOWS ID a continuous cycle during any periodof operation, heat being absorbed from the medium surrounding the evaporation chamber in order to secure the desired refrigerating eifect, which heat is carried by the refrigerant fluid to the condensing) chamber and removed from the apparatus 1yq bringing an outside-medium into heat-exc angin relation to the contents of the con ensing chamber.

85 It has been heretofore proposed to employ in compression refrigerators a refrigerant and a lubricant which-is immiscible with the refrigerant. Many liquids possessing to a greater or less extent this property have 40 been used, generall with incomplete sue-- cess, since no com i tion of refrigerant and lubricant has'been found in which the liquids do not mingle to some extent when brought together 'under the conditlons of agitation obtaining in a compression refrigerator. Mechanical separators of various types have been employed'with machines of this character to facilitate the separation of the refrigerant and the lubricant. This expedient has improved the operation but has not resulted in accomplishing a sufiiciently complete segregationof fluids to enable compression refrigerators utilizing a 617,844. Renewed dipril 27, 1927.

compound working fluid of this character to operate for long; periods without a replacement-of the lubricant Y In the present nvention, I provide a compound working fluid for a compression refrigerator which has the properties required of a refrigerant fluid as well as those rc-v quired for the satisfactory .and reliable lubrication of the compressionmechanism. In accomplishing this result, I have departed radically fromthe prior attempts to employ an" immiscible refrigerant and lubricant.

I have discovered that'by the employment of a working fluid comprising a refrigerant and alubricant which readily'mix one with the other to formia'physicalsolution or a homogeneous llqllld'Of a character that its constituents. are'soluble in each other, I am enabled to overcome completely the lubrication difliculties heretofore experienced in the operationof compression refrigerators;

' Y The-refrigerant and lubricant which com-.

prise my admixtures are of such a character that they donotseparate out into the segregated bodies under the influence of gravity orofcentrifugal action obtaining in' a compression refrigerator; In common with admixtures and solutions of this character,

a vaporization ofone or both of the constituents 'ofmy compound working fluid maybe effected by temperature or pressure changes thereof The compound working fluid may thus be considered to consist of a very intimate admixture or a physical solution of its constituent parts.

. In obtaining a complete working fluid of this character, awide'range of refrigerants and lubricants -may beemployed. I have found by experiment that ethyl chloride as a refrigerant and a mineral oil as a lubricant, which oil readily mixes with ethyl chloride, very satisfactorily meet the required conditions for eificient refrigeration and lubrication. Good results have been obtained with a mixture of one part ethyl. chloride to one or less parts of mineral oil.

The amount of lubricant required depend upon the type ofpump employed and upon the character of lubricant utilized.- One example of a lubricant which may be satisfactorily employed is a filtered mineral oil having a viscosity of about 700 to 750 second's at 100 degrees Fahrenheit, Saybolt universal viscometer, and a pour test of about zero degrees Fahrenheit. An oil of such a charactermaybe mixed with ethyl .chloride in an approximate ratio of four parts of ethyl chloride to one part ofoil. This admixture has been found under, severe centrifugal tests to exhibit no tendencies to separate into its constituents and hence may be said to constitute a true physical solution;

Another example of a lubricant which 'may' be satisfactorily employed isa filtered mineral oil having a viscosity of about 1500 seconds at 100 degrees Fahrenheit, Saybolt universal viscometer, and a pour test of about degrees Fahrenheit. An oil of such a character may also be mixed with ethyl chloride in an approximate ratio of four parts of ethyl chloride to one part of oil It is to be understood, however, that my invention is not limited to the employment of theparticular constituents. above men tioned to form the compound working fluid; or to the exact proportions of the constit uent refrigerants and" lubricants, since it will be obvious to those skilled in the .art

that my invention is susceptible of various changes and modifications, without depart; ing from the spirit thereof, and I desire, therefore, that only" such limitations shall be placed thereupon as are imposed by the prior art. or as are specifically set forth in the appended claims. W'hat I claim is:

1. A working fluid for a refrigerating 3'5 3. A wor 'ng fluid for a refrigerator com-- prising ethyl chloride and a lubricant form; ing therewith a true physical solution.

' 4. A working fluid for a refrigerator comprising ethyl chloride and a mineral oil forming'therewith a true" physical solution.

- 5. A working fluid for a'continu'ous cycle compression refrigerator comprising ethyl chloride and a lubricant forming therewith a true physical solution I 6. A working fluid for a continuous cycle compression refrigerator comprising ethyl chloride and amine'ral oil'fo'rming therewith a true physical solution.

. In testimony whereof, I. have hereunto.

subscribed my name this 30th dayof 'Jans uary, 1923. A. KUOHER. 

